Air providing system for metal converters



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I. R. LOSS AIR PROVIDING SYSTEM FOR METAL CONVERTERS Filed Nov. 15. 1961 INVENTOR lS/DOR R. L .5

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m mm MM am. B d w 1 m. w 6 o .H n I 3% w w a 0 Pressure lbs) HIS AGENT 3,137,123 AER ZRflillE-ENG SYSTEM FUR METAL 69h? E2 llsidor 12. Loss, Phillipsburg, NJL, assignor to Hngersoli- Rand ornpany, New York, N3 a corporation of New Jersey Filed Nov. 15, 1961, Ser. No. 152,446 5 @laims. (Cl. Bil-did) This invention relates to air providing systems and more particularly to a system for providing air to a metal converter.

It has been the practice to provide air to a metal converter, based on a constant pressure at the blower discharge. This type of system originated with the use of r-ciprocating blowers, wherein for a given speed of the blower its output is substantially constant. However, at the present time centrifugal and other type units, either motor or turbine driven, are used to provide air to such metal converters.

Actually, converting processes are refining means by oxidizing or by burning out impurities, such as sulphur and iron from an impure copper, wherein the initial impure metal is heated to a molten or liquid state and air or oxygen is introduced for oxidization. Inasmuch as the molten metal level is normally maintained constant, the amount of impurities can be determined by their weight, and therefore, it would be more accurate to introduce the air or oxygen on the basis of weight rather than on the basis of volume or pressure.

A blower providing air to a metal converterrnust overcome pipe losses, filter losses, tuyere losses, and the hydrostatic head of molten or liquid metal. In general, to normally determine the requirements of a blower for use in such installations, the requirements are given to cover the most severe conditions under which the blower is to operate. However, it should be readily realized that such a unit rarely will operate at such adverse conditions, and minimum operating conditions are also rarely encountered.

A blower, as any machine, has a maximum eificie; cy operating range and is capable of operating beyond such point with its efiiciency rapidly dropping off. Thus, by evaluating the converter system to be serviced to obtain a mean or normal operating condition which eliminates a number of variables in the system, a blower system providing air to the metal converter on the basis of weight of the air delivered will further reduce variable to provide a more consistently uniform product.

Accordingly, it is an object of this invention to provide an improved system for feeding air to a metal converter to obtain a substantially uniform product.

Another obiect is to provide a system for feeding air based on the weight per unit time of such air to a metal converter.

Another object of this invention is to eliminate variables from a metal converter process.

This invention contemplates a system for providing air according to weight per unit time to a metal converter, comprising a blower arrangement having a valved inlet to receive a flow of -ir and a valved outlet connected to the converter, means for measuring or sensing the flow of inlet air, barometric pressure and inlet air temperature measuring or sensing means, and control means responsive to signals representing the flow, pressure, and temperatures for the valves to provide such air to the converter at a constant weight per unit time.

Other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with accompanying drawings wherein one embodiment of the invention is illustrated by way of example. It is expressly States Patent 0 3,l97,l23 Patented July 27, 1965 understood, however, that the drawings are for illustration purposes only and are not to be construed as defining the limits of the invention.

FIGURE 1 is a schematic view of a novel blower and converter system wherein the blower system is constructed according to the invention for providing air to the converter, and

FIGURE 2 is a graphic illustration of the effect of the condition of tuyeres on the novel blower system of FIG- Referring now to the drawings, a centrifugal type blower 10 is driven by a motor or turbine 12 and has an inlet line or pipe 14 to receive air. A hood 16 is provided to protect or shield the inlet end of pipe 14 from excessive contamination, such as dust and water. The inlet line 14 houses a meter 18 to measure the ilow of inlet air and to provided a representative signal. A valve 29 is disposed in series between flow meter 18 and blower it) in line 14, and automatically controls such inlet air flow in response to the representative signal from meter 18.

The blower ill also has an automatic shut-off valve 22 to close the inlet 14 from its first stage or the blower inlet for idling.

An output line or pipe 24 from the blower 1% includes a valve 26 which is automatically operated by a signal responsive control 49, provided with override means, as is diagrammatically shown in FIGURE 1 for manual operation, and terminates in a manifold or hood 2. The manifold 28 provides air through tuyeres 32 to a converter 39. As shown, the tuyeres 32 have punches which are manually or automatically operated at regular predetermined intervals by operating means 35 to keep the tuyeres clean.

Valves 2%}, n.2, and 26 have controls 36, 38 and 49, respectively, whi h are responsive to signals such as a voltage or fluid pressure determined by the rate of air flow sensed by the flow meter 18, and compensated or modified by signals provided by barometeric pressure and inlet air temperature sensing arrangements 42 and .4, respectively, embodied in the control network. Signals from meter 18 and sensors 42 and 44 are combined in a junction box or by a signal proportioning device 48. Valve 26 may also be manually controlled as shown. Thus, by regulating the control network, air determined by its predetermined weight is provided to the converter 39. Further, a combined pressure limiting and atmospheric blowotf valve 46 in line 24 is connected to the control network for limiting or relieving the discharge air of blower It). It should be understood that signals from device 48 vary between a range from a minimum to a maximum signal in response to varyin" operating conditions sensed in the usual manner. Similarly, valve control means 35, 3S and 49 each respond to the full range or a part or" the range of such signals to the extent necessary to correctly and automatically operate valves 2%, 22 and 26, respectively, for desired flow control.

To visualize the eiiects of temperature, a constant speed blower or blower system providing twenty thousand cubic feet of air per minute (20,000 c.f.m.) when the barometric pressure is 29.92 inches of mercury (in/Hg) and the inlet air temperature is Zero degrees Fahrenheit (0 F.) and with a line pressure of fifteen pounds (15 lbs.) will deliver seventeen hundred and twenty five pounds of air per minute (1725 lbs/min). However, under the same conditions when the temperature is Fahrenheit and 101') Fahrenheit, the blower will deliver 1525 lbs/min. and 1415 lbs/min, respectively. Thus, under the same conditions, the weight of a volume of air will vary about 22% with a temperature change from (3 F. to 109 F.

Barometric pressure change will have a corresponding 3 effect on the weight per unit volume of output air from a blower.

Using the foregoing as illustrative in conjunction with a metal converter wherein the. molten metal presents a static head representing 90% of the pressure requirements of the blower system, FZGURE'Z illustrates the effect of tuyeres on system output.

A curve B representing the output of a constant speed blower with inlet air temperature at 60 F. when the barometric pressure is 29.92 in./ Hg is plotted on a graph wherein the Y axis represents constant line pressure in pounds and the X axis represents air output in cubic feet per minute or pounds per minute. Thus, curve B passes through an intersection representing lbs. line pressure and 20,000 c.f.m or 1525 lbs/min. of delivered an. t.

In accordance with the foregoing, it has been estab lished that the blower system is to operate at 15 pounds line pressure and that the molten metal provides a static head representing 90% of the line pressure, in this instance being 12 pounds. Thus, the curve CT is representative of the blower output with clean tuyeres commencingwhen the line pressure exceeds 12 pounds or the static head, and being 20,000 c.f.rn. or 1525 lbs/min. when line. pressure is 15 pounds.

Correspondingly, curves DT and PF represent the blower system output when the tuyeres are dirty and when only line friction is encountered, respectively. Therefore, from the graphic illustration of FEGURE 2, it should be readily understandable, the blower system output varies with the condition of the tuyeres 32. Accordingly, an automatic sequencing control for tuyere punches 34 or frequent use when they are manually operated is necessary to keep the tuyeres clean and maintain a constant air delivery. The foregoing example and figures are merely illustrative and are not to be construed as limits of the invention.

Accordingly, a system for providing air to a metal converter has been described in accordance With this invention wherein a blower provides air flow to a converter that is flow controlled as modified according to barometric pressure and inlet air temperature, and means are included for maintaining clean tuyeres such that the product or" the converter is substantially uniform and a number of variable conditions normally encountered are eliminated.

Although a single embodiment of the invention has been illustrated and described in detail, it is expressly understood that the invention is not limited thereto.

Various changes may also be made in the design and arrangement of parts without departing from the spirit and'scope of the invention as will now be understood by those skilled in the art.

I claim:

1. A system for providing air in accordance with its weight comprising:

(a) a blower having an inlet to receive air and an outlet to provide delivery of a predetermined amount of air,

(b) means in the blower inlet for sensing and providing signals representing inlet air fiow and the temperature thereof, i

(c) sensing means for measuring and providing signals representing barometric pressure,

'(d) and valve means disposed in series between the sensing means and the blower in the blower inlet and having actuating means connected to the sensing means to receive signals therefrom to control inlet air flow, the actuating means closing the valve means in response to signal change from the sensing means (a) a blower having an inlet to receive air and an out- 4 let to provide delivery of a predetermined amount of air,

(b) means in the blower inlet for sensing and providing signals representinginiet air flow and the temperature thereof,

(c) sensing means for measuring and providing signals representing barometric pressure,

(d) and valve means disposed in the blower inlet and outlet to control air flow to and from the blower each having actuating means connected to the sensing means and being responsive to signals therefrom.

V 3. A system for providing air in accordance with its weight comprising:

(a) a blower having an inlet to receive air and an outlet to provide delivery of a predetermined amount of air,

(b) means in the blower inlet for sensing and providing signals representing inlet air flow and the temperature thereof,

(c) sensing means for measuring and providing signals representing barometric pressure,

(d) valve means disposed in the blower inlet and outlet to control air fiow to and from the blower each 'having actuating means connected to the sensing means and being responsive to signals therefrom,

(e) and control means connected to the actuating means of the valve means disposed in the blower outlet to override control by the actuating means in response to signals from the sensing means.

4. A system for providing air in accordance with its weight comprising:

(a) a blower having an inlet to receive air and an outlet to provide delivery of a predetermined amount of air,

(b) means in the blower inlet for sensing and providing signals representing inlet air flow and the temperature thereof,

(c) sensing means for measuring and providing signals representing barometric pressure,

(d) valve means disposed'in the blower inlet and outlet to control air flow to and from the blower each having actuating means connected to the sensing means and being responsive to signals therefrom,

(e) and the actuating means of the valve means disposed in theblower inlet closing such valve means in response to signal change from the sensing means for substantially blocking inlet air flow from the blower when said blower is idling.

5. A system for providing air in accordance with its weight comprising:

(a) a blower having an inlet to receive air and an outlet to provide delivery of a predetermined amount of air,

(b) means in the blower inlet for sensing and providing signals representing inlet air flow and the temperature thereof,

(c) sensing means for measuring and providing signals representing barometric pressure,

(d) valve means disposed in series between the sensing 162113 and the blower in the blower inlet and having actuating means connected to the sensing means to receive signals therefrom to control inlet air flow,

(e) the actuating means of the valve means disposed in the blower inlet closing such. valve means in response to signal change from the sensing means for substantially blocking inlet air fiow from the blower when said blower is idling,

(f) and a relief valve disposed in the blower outlet for limiting pressure therein and having actuating means connected to the sensing means being responsive to signals therefrom for venting the blower outlet when the iniet valve means blocks inlet flow from the blower.

(References on foliowing page) References Cited by the Examiner UNITED STATES PATENTS Crawford 1 230-114 Hufi 230-5 5 Standerwick 266-30 Wunsch 230-5 Hardgrove 266-5 Gess 230-4 Codrington 230-144 Talbot 230-114 LAURENCE V. EFNER, Primary Examiner.

RAY K. WINDHAM, Examiner. 

1. A SYSTEM FOR PROVIDING AIR IN ACCORDANCE WITH ITS WEIGHT COMPRISING: (A) A BLOWER HAVING AN INLET TO RECEIVE AIR AND AN OUT LET TO PROVIDE DELIVERY OF A PREDETERMINED AMOUNT OF AIR, (B) MEANS IN THE BLOWER INLET FOR SENSING AND PROVIDING SIGNALS REPRESENTING INLET AIR FLOW AND THE TEMPERATURE THEREOF, (C) SENSING MEANS FOR MEASURING AND PROVIDING SIGNALS REPRESENTING BAROMETRIC PRESSURE, (D) AND VALVE MEANS DISPOSED IN SERIES BETWEEN THE SENSING MEANS AND THE BLOWER IN THE BLOWER INLET AND HAVING ACTUATING MEANS CONNECTED TO THE SENSING MEANS TO RECEIVE SIGNALS THEREFROM TO CONTROL INLET AIR FLOW, THE ACTUATING MEANS CLOSING THE VALVE MEANS IN RESPONSE TO SIGNALS CHANGE FROM THE SENSING MEANS FOR SUBSTANTIALLY BLOCKING INLET AIR FLOW FROM THE BLOWER WHEN SAID BLOWER IS IDLING. 